This application claims priority from German application no. 201 17 862.1 filed Nov. 6, 2001.
The present invention relates to a diesel particle filter for lowering the emission of particles contained in the exhaust gas of a diesel engine. The invention further relates to a diesel engine with an exhaust gas system and a diesel particle filter disposed in the exhaust gas system.
Diesel particle filters are applied in exhaust gas systems of diesel engines to retain the soot particles contained in the exhaust gas. The soot particles contained in the exhaust gas flow during operation of the diesel engine accumulate on the impaction-side of the diesel particle filter. In order to prevent the increase of counter pressure in the exhaust gas, the accumulated soot is removed by oxidation within the scope of a combustion process at regular time intervals or as a function of the exhaust gas counter pressure. In this way a diesel particle filter can be regenerated.
However, among the soot particles deposited on the surface of the diesel particle filter are some which are not combustible and which remain as noncombustible, inorganic components during and after such filter regeneration. Within the scope of the following explanations these components are referred to as ash. The ash is retained on the surface or in the porous filter body.
Over the operating life of the diesel engine and/or its diesel particle filters increasingly more ash accumulates on the impaction-side surface of the diesel particle filter. This causes an undesirable increase of the exhaust gas counter pressure. For this reason the diesel particle filter must be freed of these ash deposits at regular intervals. For example, DE 41 34 949 C2 or also DE 199 59 955 A1 propose for cleaning such a diesel particle filter to provide access to the diesel particle filter in the exhaust gas system both in front of and behind the filter. Directions used are in referenced to the direction of flow of the exhaust gas. Through the access a fluid can be introduced into the exhaust gas system to flow through the diesel particle filter counter to the direction of through flow of the exhaust gas and to be drawn off again through the opening located at the impaction-side in front of the diesel particle filter. Through this cleaning stream the ash is said to become detached from the impaction-side surface of the diesel particle filter and be taken out of the exhaust gas system. The fluid employed can be a liquid or gaseous phased substance.
Within the cited prior art it is also proposed that the diesel particle filter is taken out of the exhaust gas system and subsequently be freed of the ash deposits in corresponding cleaning baths. However, problematic in the known methods is that the cleaning of the diesel particle filter is insufficient and incomplete. As a rule, ash accumulations remain in the form of patches.
Building on this discussed prior art, the present invention discloses a diesel particle filter that utilizes conventional cleaning methods and obtains a better cleaning of a diesel particle filter of ash deposits.
In the present invention the impaction surface is developed such that the surface has a low binding force to the ash particles. This results in the adhesion of ash particles on this surface of the diesel particle filter occurs, at most, only with such binding forces that the ash particles can be removed from this surface of the diesel particle filter with a fluid and/or through vibrational action.
The primary aspect of the present invention is to provide a diesel particle filter which has an impact surface which allows for the easy cleaning of ash off the impact surface of the filter.
Other aspects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
In the diesel particle filter of the present invention at least its impaction-side surface is developed such that ash particles are capable of adhesion to its surface only with such binding forcesxe2x80x94if at allxe2x80x94that the ash particles can be readily removed again from the diesel particle filter by blowing a fluid in the counter flow direction or other known removal methods.